The use of a pattern yarn feed attachment such as a scroll attachment, for use in selectively feeding selected ones of a plurality of yarns to the needles of a tufting machine for tufting a pattern in the face of an article in accordance with a predetermined pattern is known. Such pattern yarn feed devices control the rate at which selected ones of the tufting yarns are fed to selected ones of the tufting needles as the needles are reciprocably passed through a backing material advanced laterally underneath the needles of the tufting machine, through a tufting zone, while tufting the patterned article. The yarn feed rate will in turn control the pile height of the yarns, or tufts, sewn into the backing material, usually by causing certain ones of the tufting yarns to be "back robbed" from the previously sewn tufts in the backing material so that a "full" height tufted pile is not sewn relative to the pile height of the surrounding tufts of yarn. The degree to which the yarn is back robbed will determine how much of that yarn is visible in the face of the finished article.
With the known pattern yarn feed devices, it has usually been necessary, when a yarn breaks or when different yarns are selected to be fed to different selected ones of the needles of the tufting machine during a pattern changeover, i.e., when the pattern to be tufted in the face of the article is changed from a first pattern to a second differing pattern, to re-wrap such yarns about the appropriate yarn drive or feed roll, or rolls, and then re-thread each of the tufting needles. This threading and/or re-threading of the needles is generally a laborious and time intensive process as each yarn must be separately wrapped about the appropriate yarn drive roll and then threaded or re-threaded through a respective one of what may be several hundred tufting needles thereafter. This typically is required each time there has been a change in the yarn feed sequence, i.e. the pattern, of the tufting yarns used to produce the article on the tufting machine.
As the operating speeds of tufting machines have increased due to improvements in the design, construction, and control of tufting machines and their related drives, more precise control over the feed rates of the yarns as they are being fed to the needles of these tufting machines is necessary in order to ensure that an acceptable pattern definition is tufted into the articles being produced. This in turn has required that improved yarn feed devices be developed which can feed the selected tufting yarns to the desired needles of the tufting machine at the increased rates of speed necessary in order to permit these increased production rates to be realized. Such improved yarn feed devices, however also must maintain precise control over the individual yarns so that an acceptably defined pattern is tufted in the face of the articles so produced in order to allow tufted article manufacturers to fully realize, and thus obtain the benefit of, the increased operating efficiencies permitted by these tufting machines to produce high quality tufted articles.
What is needed, therefore, but seemingly unavailable in the art, is an improved tufting machine pattern yarn feed device that allows for a high degree of precision in the control of the yarn feed rates to control of the quality of the patterns being tufted in the articles being so produced. Moreover, there is a need for such an improved pattern yarn feed device which will permit a tufting machine operator to quickly and easily change the sequence of yarns fed to the needles across the width of the tufting machine, and to be able to do so within easy reach while standing on the floor of the manufacturing facility within which the tufting machine is situated, or while standing on a work platform positioned with respect to the tufting machine without otherwise requiring the use of additional staging, platforms, and/or ladders to reach the pattern yarn feed device.
What is also needed is an improved tufting machine pattern yarn feed device which dispenses with the necessity of cutting the yarns during pattern changeover in order to quickly pass the yarns about different yarn feed rolls, and which will not otherwise require that the yarns be re-threaded through the needles during such a pattern changeover. Such a construction should preferably eliminate the necessity of manually wrapping individual ones of a yarns separately about the selected yarn feed roll, or rolls, in order to adjust the feed rate of the respective yarns. Additionally, what is needed is such an improved tufting machine pattern yarn feed device that allows for the amount of yarn wrap about selected ones of the yarn feed rolls to be quickly and easily adjusted as desired, or as required, for control of the yarns being used to tuft the pattern in the face of the article, and which allows a machine operator to selectively pinch selected ones of the yarns against the yarn feed roll with a pinch roller for still greater control over the feeding of the yarns.